In laser applications which require high power densities in master oscillators or amplifiers such as for use in laser enrichment, burning and other problems can occur at the interface between the actively lasing medium and the containment walls for the laser medium. A possible solution to this difficulty is the use of the free jet laser as, for example, shown in U.S. Pat. No. 3,766,489. The free jet eliminates the boundary layer problem in the region of the lasing medium bordering the containment walls.
For use in the laser enrichment application, the free jet must be carefully dimensioned to insure a high quality laser beam, that is one free from distortion and excessive divergence. This is important because it is required that the laser beam for the enrichment application travel great distances with low beam divergence. Such beam quality requires that the actively lasing region of the free jet have precisely plane parallel surfaces which cannot be achieved with such prior art nozzles.